DVD-R

• DVD-R discs are designed according to specifications that are supported by the DVD Forum, an organization responsible for setting DVD compatibility standards. DVD-R discs therefore will function in most standard DVD players and generally are regarded as the most reliable. DVD-R discs can hold up to 4.7 gigabytes of data (early versions only supported 3.95 GB). These DVDs are usually manufactured with an organic dye compound that gives the reflective side of the disc a purple color.
  
  

DVD-RW

• The main difference between a DVD-RW disc and a DVD-R disc is that the former can be erased and rewritten with new data. A typical DVD-RW disc can be reformatted about 1,000 times before it wears out. The reflective side of these discs is gray. A DVD-RW disc can hold 4.7 GB of data.
  
  

DVD-RAM

• Developed by Panasonic, the DVD-RAM recordable disc works more like a hard disk drive than a standard recordable disc. Data can be written or erased at any time, as these discs do not need to be finalized. The discs are small, contained in a plastic sleeve and often used for video cameras that record direct to DVD. Of all of the recordable DVD disc formats, this is the least compatible with standard DVD players.
  
  

DVD+R/DVD+RW

• The "Plus" DVD recording formats are not authorized by the DVD Forum but they can still play in most DVD players. The most notable difference between these and standard DVD-R discs is the ability to record without finalizing the disc. Most drives that can burn DVD+R discs also can burn DVD-R discs; however, early DVD-R drives cannot write to DVD+R discs. As with DVD-Rs, DVD+R discs hold up to 4.7 GB of data. Rewritable "plus" discs (DVD+RW) are also available.
  
  

Dual Layer Formats

• The dual layer formats, DVD-R DL and DVD+R DL, can only be recorded on optical drives that specifically support this format. Dual-layer discs have a second layer of recordable space, allowing 8.5 GB of data to be written to the disc. These discs are useful for creating masters for professionally pressed DVD video discs. Dual-layer discs have the same compatibility as single-layer discs.